Lots of writers enjoy speculating on vice presidential possibilities (myself included). As a result, we get maddeningly long lists of potential running mates which might ...

Lots of writers enjoy speculating on vice presidential possibilities (myself included). As a result, we get maddeningly long lists of potential running mates which might very well bear little resemblance to the actual short lists of the candidates. So, for the sake of everyone's sanity, I'd like to do the exact opposite: speculate on who won't get picked.

Truth be told, it's been so long since a sitting governor ended up as a running mate (the last one was Spiro Agnew in 1968) that it's hard to know what standards John McCain, Barack Obama or Hillary Clinton will use. But, because McCain, Obama and Clinton are all U.S. senators, there's a good chance that 40-year drought will end, thanks to the irresistible force of vice presidential selection: balance.

In spite of the uncertainty, I can think of six key reasons to exclude certain governors, which I've ranked roughly in order from most prohibitive to least. 1) They're foreign born. 2) They're unpopular back home. 3) They're significantly out of step with their party on key issues. 4) They've just been elected for the first time in the past two years. 5) They're from small states. 6) They're facing tough reelection bids this year.

Note that extenuating circumstances can keep many of these from being absolute dealbrakers. Charlie Crist is the popular governor of Florida, so he stands a chance despite being new to office.

Note also that, while I've placed each governor in one of the six categories, in some cases it's a combination of factors that rules them out. Colorado Democratic Gov. Bill Ritter isn't just pro-life, he's also newly elected. Don Carcieri, Rhode Island's Republican governor, has seen his approval ratings take a hit lately, in addition to being the governor of Rhode Island.

Without further ado, here's the list, along with some explanations.

1) Foreign born. Does Article Two of the Constitution implicitly require that the vice president, in addition to the president, be a natural-born citizen? Or would a foreign-born vice president not be allowed to take over the office of the president? I doubt we'll ever find out. (UPDATE: In the comments, Fred notes the 12th Amendment of the Constitution, which includes, "But no person constitutionally ineligible to the office of President shall be eligible to that of Vice-President of the United States.")

-Arnold Schwarzengger (R-CA)

-Jennifer Granholm (D-MI)

2) Unpopular. It's always a bonus when a running mate can help the ticket carry a state. Well, these governors are unpopular enough that they might cause the ticket to lose their home states. Plus, their low approval ratings would guarantee negative press coverage of the selection.

-Jon Corzine (D-NJ)

-Matt Blunt (R-MO)

-Rod Blagojevich (D-IL)

-Martin O'Malley (D-MD)

3) Out of step with the party. Republican Gov. Jodi Rell of Connecticut signed the nation's first gay civil unions law that wasn't prompted by a court order. She's also pro-choice. She's one of a group of governors who regularly commit partisan heresy to the point that it's hard to imagine them on a presidential ticket.

-Jodi Rell (R-CT)

-Dave Freudenthal (D-WY)

-Brad Henry (D-OK)

-Joe Manchin (D-WV)

-Linda Lingle (R-HI)

-Jim Douglas (R-VT)

4) Newly elected. As I argued the other week when writing about Alaska Gov. Sarah Palin and Louisiana Gov. Bobby Jindal, the resumés of runnings mates actually might matter more than the resumés of the presidential candidates themselves. Voters have all of Barack Obama's speeches, press conferences and debate performances to decide whether he's ready to be president. But the media can define running mates in a matter of days (see: Quayle, Dan), largely on the basis of biographical information. That means governors who took office in 2007 or 2008 (without serving in a major office beforehand) are unlikely to win the veepstakes.

-Mike Beebe (D-AR)

-Chet Culver (D-IA)

-Deval Patrick (D-MA)

-David Paterson (D-NY)

-Steve Beshear (D-KY)

-Jim Gibbons (R-NV)

-Bill Ritter (D-CO)

5) Small state. Here's a thought experiment: Former Vermont Gov. Howard Dean nearly won the Democratic nomination for president in 2004. But, without a presidential run, would Dean, a successful governor for a decade, ever have been seriously considered as a vice presidential candidate? I think the answer is no. Large state governors tend to be better known nationally (quick, name the governor of North Dakota) and choosing a political unknown is regarded as risky.

-John Baldacci (D-ME)

-John Lynch (D-NH)

-Butch Otter (R-ID)

-Mike Rounds (R-SD)

-Ruth Ann Minner (D-DE)

-Don Carcieri (R-RI)

-John Hoeven (R-ND)

6) Tough reelection. Running for two offices at once often raises legal problems. Invariably, it creates political headaches, as voters question the candidate's commitment to either position. In 2000, Joe Lieberman was reelected to the U.S. Senate as he served as Al Gore's running mate, proving you can run for something else while seeking the vice presidency. But that doesn't make it easy, especially for governors whose opponents are more than nominal.

-Christine Gregoire (D-WA)

-Mitch Daniels (R-IN)

I could add a seventh category for governors who aren't noteworthy enough for there to be any particular reason for them to be picked (Ted Kulongoski, Dave Heineman, Mike Easley, I'm looking at you), but I suppose I've done enough eliminating for one day.